feat(test): add karma plugin (angular#1437)

Author: filipesilva

addon/ng2/blueprints/ng2/files/package.json

@@ -41,6 +41,7 @@
     "jasmine-spec-reporter": "2.5.0",
     "karma": "0.13.22",
     "karma-chrome-launcher": "0.2.3",
+    "karma-coverage": "^1.0.0",
     "karma-jasmine": "0.3.8",
     "karma-remap-istanbul": "^0.2.1",
     "protractor": "4.0.3",